Back-spacing device for type-writers.



C. MERCER.

BACK SPAGING .DEVICE FOR TYPE WRITERS.

APPLICATION FILED JAN.31,1910.

PatentedAug'. 2, i910.

qu ua nto@ ,Pf/maw CEL CHARLES MERCER, Gl? IYIUSKQGESE, OKLAHOMA.

BACKHSPACJING DEVCE FOR TYPEnWRITERS. I

Speelcaton of Letters Patent.

Application filed January 3l, 1910.

patented Aug'. 2, iiit.

Serial No. L120.

Be it known that l, @Henna-:s Meneer, a

ing mechanism tor such machines.

The primary object ot the invention is to provide a mechanism ot this character operated by a key or lever and adapted, when actuated, to move 'the carriage back accurately one space at a time.

Another object is to provide a' safety device or attachment for use in connection with such mechanism whereby the parts will be prevented from becoming locked or injured in case the. back-spacing key and a character key are struck at the same time. To this end the back-spacing mechanism and escapeincnt are so arranged that the latter, when operated, does not .prevent the other from moving, but simply renders it teun porari ly inoperative.

lilith the abov\l and other objects in view, andto improve and generally simplify devices oit this character, my invention consists in the construction and arrangement otparts hereinafter described, and illustrated in the accon'ipanying drawings, in which :w

Figure l is a 'detailed elevation ot the escapement and back-spacing mechanisms.

V Fig. 2 is a similar View ot' the back-spacing mechanism alone. Fig. 3 is a conventional side elevation of a typewriting niachinc, showing my improvements applied thereto. Fig. l is a sectional View taken on the line 4-l of Fig. l.

rll/ly invention is especially adapted for use in connection with the Remington machine, and is so illustrated in the drawings, but, with slight changes, and in certain of its aspects it may be advantageously applied to machines of other makes.

Referring to the drawings in detail, l deS- ignates a rack secured to the typewriter carriage and movable therewith. ln engagement with this rack is a pinion 2, fixed upon a shaft 3 journaled in the trame-ot the inaehine. Fast on the outer end ot the shaft 3 are thel escapement wheels 4, which cooperate with a pawl 5, pivetally mounted in one arm of a bell c ank lever (l, carried on 'the shaft a rock shalt i. 'To the outer end ot this bell crank lever is connected one end ot a link 8, the other end ot which is secured to a bar 9 on which the levers 10, carrying the character keys ll, bear. lVhen therefore, any character key is depressed, the pawl 5 vis caused to oscillatc, and thus permit one tooth ol" the wheels l to pass, the carriage being urged torward by a spring (not shown) in a well known manner. 'lheabove described cscapemcnt mechanism is ot the' usual constructit'm Vfound in the type oit machine rel'crred to above. lt is otten necessary or desirable, however, in making corrections, doing tabulating, etc., to move the carriage back a space or two, in a direction the reverse ot that in which the spring is nl 'ging it, and it is also essential that this back-spacing be done accurately. My improved lnwk-spacingmechanism is designed to accomplish thcsc results, and will now he described.

Fast on the shal't. 3, and inst inside thc. escapcmcnt wheels 4, l arrange a toothed wheel 12, otx approximately the salme. diameter. A swinging dog l is provided at one end with tceth lst, adapted to engage the teeth o'lE the wheel l2, and at thc other end is pivoted at l5 to a bracket lli, which is itself pivotally mounted at its other end on The dog- 153 is provided, in- 'terniediate its ends, with a transverse hinge 17, the purpose of which will he hereinafter described, and a leaf springlS is rigidly secured to the bracket l() and'bears against the side of the dog :lil reinote from the escapement wheels. Pivoted to the dog 13 is one end oit a link 19, the other end oi' which is secured to one end of a key lever 20, pivotcd as at 21 to a fixed support, and terminating at its forward end in a key L12, or other suitable button or thumb pieces. W hen it is desired to back-space, the forward end of key lever 2O is depressed, thus thrusting the link 19 upward. This, in turn, forces the teeth 14 of the dog 13 into engagement with the toothed wheel l2, and then, by a further movement, the entire dog and bra'cket 16 are given a bodily swinging motion around the shat't 3 as a center. This results in ttu'ning the wheel 12, and with itthe pinion 2, and thus the carriage is shift. n

ed back one space. To shift another space, the key 1s released, the dog drops back by gravity to the position shown in Fig. i2, and

when the key is again depressed, the dog iillizii il w rmi 'lt will tlmlic semi llml' if lmw provided :L badi-Spacing; n'iciflmnism porisossmg grunt isimplicity, accuracy, snfcif nifl oili'sr desirable feature and .it is thuug il: lli@ mmierous advantages of my invention will be, l'emlily apprecinl'cd li): l'iosc sikilicd lli@ ui.

flint l claim is:

l, In a typuwrilingmachins, ai ::i1i'iug,an escnpement mcclmnimm bacl spacing 

